Grease compositions



United States Patent GREASE COMPOSITIONS Gordon D. McLeod, Hammond, Ind., and William L.

Rittschof, Chicago, 111., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana 7 No Drawing. Application October 28, 1950 Serial No. 192,824

10 Claims. (Cl. 252-33) Greases of the present invention comprise essentially a normally liquid oleaginous compound, preferably a hydrocarbon oil, and from about 0.5% to about 70%, and preferably from about 1% to about 20%, of a guanidine sulfonate. The guanidine sulfonate can be the guanidine or alkyl guanidine salt of hydrocarbon oil sulfonic acids obtained in the treatment of hydrocarbon oils with strong sulfuric acid or of alkanesulfonic acids or of arylsulfonic acids, alkaryl sulfonic acids, and mix' tures thereof. The sulfonic acids can be preferentially oil-soluble sulfonic acids or preferentially water-soluble sulfonic acids. However, when the guanidine salts of preferentially water-soluble sulfonic acids, i. e. low molecular weight, are employed, they are used in combination with salts of preferentially oil-soluble sulfonic acids as hereinafter more fully described.

The hydrocarbon oil sulfonic acids which can be used advantageously to produce the guanidine sulfonates of this invention are those obtained in the treatment of hydrocarbon oils, such as mineral or petroleum oils with strong sulfuric acid, such as concentrated or fuming sulfuric acid. In the treatment of petroleum oils to obtain highly refined products of the type of electrical insulating oils, turbine oils, technical White oils and medicinal White oils, etc., the petroleum oils are treated successively with a number of portions of concentrated sulfuric acid (i. e. above about 95% strength) or fuming sulfuric acid. A variety of sulfur-containing compounds are formed by the chemical reaction of the sulfuric acid upon the oil, including sulfonic acids, organic esters of sulfuric acid, partial esters of sulfuric acid, etc. -Most of these compounds are relatively insoluble in the oil under the treating conditions and separate from the oil, together with the unreacted sulfuric acid, as a sludge, which is separated from the oil after each acid treatment. The sulfuric acid is usually added in dumps of about one-half pound per gallon of oil, the total quantity of acid treated depending upon the oil treated and the desired final product; usually, from about three pounds to about nine pounds of sulfuric acid per gallon of oil are used. Someof the sulfonic acids resulting from the treatment of the oil with the sulfuric acid are preferentially oil-soluble andremain in the oil layer after removal of the acid sludge. Because of the characteristic mahogany color of these preferentially oil- -soluble sulfonic acids,.they. are known in the petroleum art as mahogany acids. The guanidine salts of such mahogany acids can be obtained by neutralizing the acidtreated oil with guanidine basic salt, such as for example,

Another object 7 guanidine carbonate, etc., to form guanidine sulfonates which are then extracted from the oil by treatment with 50% to aqueous alcohol solutions or other suitable means.

The preferentially oil-soluble guanidine sulfonates can also be obtained by neutralizing the acid-treated oil with an alkaline agent, such as an alkali metal hydroxide, to form the corresponding sulfonate, which then can be extracted from the oil as herein-before described. The alkali metal sulfonate recovered from the acid-treated oil can then be acid-treated to recover the sulfonic acid which can then be converted to the guanidine sulfonate by neutralization with guanidine carbonate, etc.

The preferentially oil-soluble petroleum sulfonic acids have molecular weights ranging from about 350 to about 525. While any of these sulfonic acids can be used, We prefer to use thosehaving molecular weights ranging from about 400 to about 500, particularly those having molecular weights in the range of about 420 to about 480. In preparing the guanidine sulfonate from the petroleum sulfonic acids, we can use substantially oilfree sulfonic acids, although for practical purposes, blends of oil and sulfonic acids can be used. Usually, the sulfonic acids are recovered as blends of about 40-50% sulfonic acid in hydrocarbon oil.

The acid sludge separated from the acid-treated hydrocarbon oil contains preferentially water-soluble sulfonic acids which because of their characteristic green color, are commonly referred to as green acids. acids can be recovered from the acid sludge by adding water to the sludge to dilute the sulfuric acid therein to a concentration of 20% to 30%, at which concentration the green acids separate to form a supernatant layer; or the green acids can be extracted from the sludge with water-soluble solvents, such as alcohols, ketones and the like, or with mixtures of organic solvents and water. The preferentially water-soluble sulfonic acids or green acids, so recovered can be converted to the corresponding guanidine sulfonate by neutralization with a guanidine basic salt, such as for example, guanidine carbonate, etc.

Guanidine alkanesulfonates suitable for use in the present invention can be prepared by reacting a guanidine basic salt, e. g., the carbonate, with alkanesulfonic acids having from about 1 to about 20 carbon atoms in the alkyl radical, although We prefer to use those having froml to about 6 carbon atoms in the alkyl radicals. The latter can be prepared by the oxidation of hydrocarbon polysulfides in the presence of a catalytic quantity of a nitrogen oxide in a manner described in U. S. Patents Nos. 2,433,395, 2,433,396 and 2,489,318. The guanidine salts of sulfonic acids can be prepared by neutralizingalcoholic or aqueous solutions of the alkanesulfonic acids with a guanidine alkaline salt, e. g. the carbonates. The alkanesulfonic acids such as methane, ethane, propane,.butane or hexane sulfonic acids are suitable for use in the present invention. Particularly suitable are the guanidine salts of mixed alkanesulfonic acids, such as a mixture of methanesulfonic acid, ethanesulfonic acid, and propanesulfonic acid having average molecular weights of about -115.

We can also use the guanidine salts of other sulfonic acids, such as those obtained by the sulfonation of olefin polymers, and by the sulfonation of aromatics and alkylated aromatics. The sulfonic acids obtained by the sulfonation of olefin polymers having at least 22 carbon atoms in the molecule and the sulfonic acids obtained by the sulfonation of alkylated aromatics having at least about 19 carbon atoms in the alkyl chain are preferentially oil-soluble. i

In accordance with the present inventi The greensalts of preferentially oil-soluble sulfonic acids can be used alone in admixture with the desired hydrocarbon oil. However, when using guanidine salts of preferentially oil-insoluble sulfonic acids, such as the low molecular weight alkanesulfonic acids, from about .5 to about 20%, and preferably from about 1% to about 5% of such guanidine sulfonates are used in combination with from about 0.4% to about 50%, and preferably from about 2% to about of a salt of preferentially oilsoluble sulfonic acids, particularly the salt of a preferentially oil-soluble petroleum sulfonic acid of the type herein-before described. The alkali metal salts, such as sodium, potassium, and lithium, the alkaline earth salts, such as barium, calcium, strontium, and magnesium and/or the guanidine salts of mahogany acids having molecular weights in the range of from about 450 to about 500, are preferred although heavy metal salts of such acids can also be used.

Specific examples of guanidine sulfonates which can be used in preparing greases in accordance with the present invention are the following:

Guanidine para toluene sulfonates Guanidine mixed toluene sulfonates Guanidine benzenesulfonate Guanidine mixed xylene sulfonates Guanidine naphthalenesulfonate Guanidine octylsulfonate Guanidine cetylsulfonate Guanidine salts of preferentially oil-soluble petroleum sulfonic acids having molecular weights within the range of from about 410 to about 500 Guanidine salts of preferentially water-soluble petroleum sulfonic acids Guanidine methanesulfonate Guanidine ethanesulfonate Guanidine propanesulfonate Guanidine butanesulfonate Guanidine hexanesulfonate Guanidine salt of mixed methane, ethane, and propanesulfonic acids Guanidine salt of sulfonated polyisobutene having a molecular weight of about 1000 Guanidine salt of sulfonated polybutene alkylated benzene,

etc.

Octyl guanidine benzenesulfonate Diethyl guanidine ethanesulfonate Dibutyl guanidine mahogany soap Tetramethyl guanidine toluene sulfonate Although the guanidine sulfonates of the type herein described are of suitable use in the preparation of greases in accordance with the present invention, they are not necessarily equivalent in their effectiveness. It is, therefore, not to be implied that all of the guanidine sulfonates of the classes herein-described are equivalents for the purpose of the present invention.

Greases of the type described can be readily prepared by stirring the oil-soluble guanidine sulfonate or mixtures of oil-soluble sulfonates and oil-insoluble guanidine sulfonates in admixture with a hydrocarbon oil at a temperature of from about 200 F. to about 400 F. to effect a solution of the sulfonates in the oil, and then permitting the mixture to cool to room temperature.

The liquid vehicle of the grease can be any liquid lubricant, either natural or synthetic, usually having Saybolt Universal viscosities in the range of from about 65 seconds at 100 F. to about 400 seconds at 210 F., capable of being used in grease compositions. Examples of such vehicles are hydrocarbon oils, i. e., petroleum oils, and synthetic hydrocarbon lubricating oils, such as for example, those obtained by the polymerization of olefins, and oils in the lubricating oil range obtained in the Fischer- Tropsch Process. Other suitable synthetic oleaginous compounds are aliphatic dicarboxylic acid esters of the type disclosed in U. S. 2,450,222, the esters of dihydroxy 4 thioether, such as are disclosed in U. S. 2,451,895, silicone polymers and the monohydroxy 1,2 polyoxypropylene aliphatic monoethers of the type described in U. S. 2,448,664, etc. The type of oil and the viscosity selected will depend upon the intended use and service for the grease.

In addition to the guanidine sulfonate, greases prepared in accordance with the present invention may contain other constituents such as for example E. P. agents, for example chlorine and/or sulfur-containing compounds, pourpoint depressors, for example, condensation products of the type described in U. S. 1,963,917 and 1,963,918, oiliness agents, rust inhibitors, antioxidants, the alkali metal and/ or alkaline earth soap of high molecular weight fats and fatty acids, for example, tallow, lard, palmitic acid, stearic acid, oleic acid, animal fatty acids, etc.

The following specific examples further illustrate the present invention. It is to be understood that the examples are for illustrative purposes only and should not be regarded as limiting the scope of the invention:

Example I:

1.2% guanidine alkanesulfonate 1 2.2% sodium mahogany soap 2 96.6% hydrocarbon oil (S. U. S. at 100 F.210

215) Example II:

3.0% guanidine alkanesulfonate 1 5.2% sodium mahogany soap 2 91.8% hydrocarbon oil (S. U. S. at 100 F.--210- 215) Example III:

0.9% guanidine alkanesulfonate 1 2.7% sodium mahogany soap 2 48.2% petroleum oil (S. U. S. at 100 F.210-215) 48.2% petroleum oil (S. U. S. at 210 F.95) Unworked penetration at 77 F. (30 grams)315 Worked penetration at 77 F. (30 grams)320 Example IV:

1.54% guanidine alkanesulfonate 1 4.60% sodium mahogany soap 2 2.50% chlorinated hydrocarbon 0.50% pourpoint depressor 90.86% hydrocarbon oil (S. U. S. at F.--210 215 Example V:

9.0% guanidine mahogany soap 3 I 91.0% hydrocarbon oil (S. U. S. at 100 F.--210- 215) Example V1:

5.1% guanidine mahogany soap 3 94.9% hydrocarbon oil (S. U. S. at 100 F.--210- 215) Example VII:

3.0% guanidine toluenesulfonate 5.0% sodium mahogany soap (430 molecular weight) 2.5% chlorinated hydrocarbon 0.5% pourpoint depressor 89.0% hydrocarbon oil (S. U. S. at 100 F.-210

215) V Unworked penetration at 77 F. (30 grams)-296 Worked penetration at 77 F. (30' grams)-296 Example VIII:

3.0% guanidine benzenesulfonate 5 .0% sodium mahogany soap (430 molecular welght) 2.5% chlorinated hydrocarbon 0.5 ourpoint depressor 89.0% hydrocarbon oil (S. U. S. at 100 F.--210- 215 UI1WOI 'k6d penetration at 77 F. 30 grams)248 Worked penetration at 77 F. (30 grams)- 265 Prepared from mixed methane, ethane, and propane alkanesulfonic acids having an average molecular weight of -115.

9 Prepared from mahogany acidshavmg a molecular weight of 470-500.

3 Prepared from mahogany acid having a molecular weight of about 430.

In the above examples the sodium mahogany soap used was a blend of 42% mahogany soap in a petroleum oil.

The product of Example I was prepared by heating a mixture of the guanidine alkanesulfonate, mahogany soap and oil to a temperature of about 250 F. with slight stirring. The grease obtained upon cooling was a thermally reversible, unctuous, clear, mechanically stable product. The product did not leak oil when heated to a temperature of 200 F. for twenty-four hours and did not change structure on ageing. The product was non-fibrous and was similar to a cup grease containing 8% to 10% calcium fatty soap. The product was stable to working and retained its grease-like structure even when worked in the presence of water. The product of Example II was similar in its properties to the product of Example I. The product of Example IV had an unworked penetration at 77 F. (38 grams) of 326 and a worked penetration of 329. The grease did not solidify at 25 F. and showed no oil separation after 16 hours at 175 F. The product of Example V was prepared by heating a mixture of the guanidine mahogany soap and oil to a temperature of about 300 F., with stirring, to effect solution of the soap, and the oil. Upon cooling, a grease product having an A. S. T. M. drop point of 295 F. was obtained. The product of Example VI was prepared by heating and stirring a mixture of the guanidine mahogany soap and oil at a temperature of about 215 F. Upon cooling, a grease product was obtained which had an A. S. T. M. drop point of 285 F. and an A. S. T. M. penetration of 360 at 77 F.; the A. S. T. M. penetration at 0 F. was 255. The product showed no oil leakage at 230 F. for twenty-seven hours, was non-corrosive to copper and had a Navy Water Absorption of 70%. The grease had a smooth structure and was thermally reversible.

Greases of the present invention find application as a multi-purpose automotive grease, including stearing gear grease, including ball bearing lubricants as washing machine lubricants, etc. Furthermore, because of their property of being thermally reversible, such products can be used in such services where cup greases are not satisfactory.

Percentages given herein and in the appended claims are weight percentages unless otherwise specified.

Grease compositions containing a water-soluble guanidine salt of a low molecular weight acid and a preferentially oil-soluble hydrocarbon sulfonate is claimed in copending G. D. McLeod application Serial No. 200,110 filed December 9, 1950, which issued as U. S. 2,620,301 December 2, 1952.

While we have described our invention by reference to specific embodiments thereof, these have been given by way of illustration and the invention is not to be limited thereby but includes within its scope such modifications as come within the spirit of the appended claims.

We claim:

1. A lubricant comprising at least 1 weight percent of a guanidine salt of a preferentially oil-soluble petroleum sulfonic acid, incorporated in a mineral oil.

2. A grease lubricant comprising a mineral oil incorporated with at least 1 weight percent of a guanidine salt of a preferentially oil-soluble petroleum sulfonic acid.

3. A grease composition comprising a normally liquid hydrocarbon oil and from about 1% to about 20% of a preferentially oil-soluble guanidine petroleum sulfonate.

4. A grease composition comprising a normally liquid hydrocarbon oil, and from about 1% to about 20% of a guanidine salt of a preferentially oil-soluble petroleum sulfonic acid having a molecular weight of from about 400 to about 500.

5. A grease composition comprising a normally liquid hydrocarbon oil, and from about 1% to about 20% of a guanidine salt of a preferentially oil-soluble sulfonic petroleum sulfonic acid having a molecular weight of about 450.

6. A grease composition comprising a normally liquid oleaginous compound and a sulfonic acid salt selected from the group consisting of a guanidine salt of a preferentially oil-soluble petroleum sulfonic acid, and a mixture of a guanidine salt of a preferentially oil-insoluble sulfonic acid and a salt of a preferentially oil-soluble sulfonic acid, said guanidine salt of apreferentially oil-soluble sulfonic acid being used in amounts of from about 0.5% to about and said guanidine salt of a preferentially oil-insoluble sulfonic acid and said salt of a preferentially oilsoluble sulfonic acid being used in amounts of from about 0.5% to about 20% and from about 0.4% to about 50%, respectively, in said mixture.

7. A grease composition comprising a normally liquid hydrocarbon, from about 0.5 to about 20% of a guanidine salt of an alkanesulfonic acid, of from 1 to about 6 carbon atoms, and from about 0.4% to about 50% of a salt of a preferentially oil-soluble sulfonic acid.

8. A grease composition comprising a normally liquid hydrocarbon oil, from about 0.5% to about 20% of a guanidine salt of alkanesulfonic acids having from 1 to 6 carbon atoms, and from 0.4% to about 50% of a metal salt of preferentially oil-soluble petroleum sulfonic acids.

9. A grease composition comprising a normally liquid hydrocarbon oil, from about 0.5% to about 20% of a guanidine salt of alkanesulfonic acids having an average molecular weight of about to 115, and from about 0.4% to about 50% of an alkali metal salt of preferentially oil-soluble petroleum sulfonic acids having molecular weights within the range of 450 to about 500.

10. A grease composition as described in claim 9 in which the alkali metal salt of the preferentiallyoil-soluble petroleum sulfonic acid is the sodium salt.

References Cited in the file of this patent UNITED STATES PATENTS 2,372,588 Larsen Mar. 27, 1945 2,444,970 Zimmer et al. July 13, 1948 2,535,101 Sproule et al Dec. 26, 1950 2,660,562 Axe et al. Nov. 24, 1953 

8. A GREASE COMPOSITION COMPRISING A NORMALLY LIQUID HYDROCARBON OIL, FROM ABOUT 0.5% TO ABOUT 20% OF A GUANIDINE SALT OF ALKANESULFONIC ACIDS HAVING FROM 1 TO 6 CARBON ATOMS, AND FROM 0.4% TO ABOUT 50% OF A METAL SALT OF PREFERENTIALLY OIL-SOLUBLE PETROLEUM SULFONIC ACIDS. 